In a turbo machine having a row of stator blades and a row of rotor blades, the passage between the blades is surrounded by a wall on the radial inside and a wall on the radial outside (referred to as platforms, bands, shrouds or the like). The working fluid flowing out from the passage between blades of one blade row flows into the passage between blades of the next adjacent blade row. A gap is provided between the wall pair of axially adjacent blade rows (for example, refer to Patent Document 1). The presence of the gap tends to cause a turbulence of the flow close to the wall surface.
[Patent Document 1] U.S. Pat. No. 6,416,289 (FIG. 6)